Place clean, dry metal sheet pans in the freezer overnight or for at least 8 hours until freezing cold.

In a bowl, whisk eggs and sugar until light. Whisk in melted butter, milk, and vanilla. Gently fold in flour and salt until just combined.

Divide the batter evenly into 6 small bowls. Add 1-2 drops of different colored gel food coloring to each bowl to create the rainbow colors. Mix well.

Heat waffle cone maker. Pour one colored batter onto the center and cook for 1-2 minutes until set but still pliable.

Immediately remove the hot waffle and drape it over a taco rack or rolling pin. Hold it in a 'U' shape for 15-20 seconds until it cools and hardens. Repeat for all colors.

In a large pitcher or bowl, whisk together the heavy whipping cream, sweetened condensed milk, vanilla extract, and salt until smooth.

Remove a freezing cold sheet pan from the freezer. Pour about 1/2 cup of the ice cream base onto the pan. Use a spatula to spread it rapidly into a paper-thin, even layer.

Return the pan to the freezer for 4-6 hours until the ice cream is frozen solid.

Remove the pan from the freezer. Working quickly, place a metal scraper at a 45-degree angle at the edge of the ice cream and push forward firmly to scrape the ice cream into tight rolls.

Use tongs to gently pick up the ice cream rolls and nestle them inside the colored waffle cone taco shells.

Top generously with whipped cream, chocolate syrup, caramel, sprinkles, toasted marshmallows, and candies. Serve immediately before melting.